1. Field of Invention
This invention relates generally to improvements in toilet flush apparatus and, more particularly, to those improvements which enable, selectively, either a full flush or a partial flush of the water in the flush tank.
2. Description of the Prior Art
In recent years, it has become more and more apparent that our natural resources are not as plentiful as they were once believed to be. It came to be realized that even water, one of our most plentiful of natural resources, was becoming threatened. As a result, efforts began to conserve more natural resources, including water. It also came to be realized that one device, in particular, utilized daily by individuals, namely a toilet, consumes very large amounts of water in its operation. Although a full capacity of the flush tank for a toilet may be necessary in order to dispose of solid wastes, a much smaller quantity of flush water is effective to dispose of liquid wastes. Hence, if a toilet performs a full flush even when disposing of liquid wastes, the consumption of water in the disposal process is unnecessary and excessive. When such excessive usage by an individual is multiplied by the size of the population, it can be appreciated that the quantity of water used needlessly in a day's time is very great indeed.
When concerned people first came to realize this situation, it was not unusual for them to place bricks, rocks, or other water displacing articles in the flush tank to thereby reduce the volume of water available for a flush. It also came to be known to place weirs or dams in the flush tank surrounding the outlet valve, similarly for the purpose of reducing the volume of water in the tank available for flushing. Such constructions are disclosed in U.S. Pat. Nos. 3,259,918 and 3,731,324, which recite the common problems of securing and sealing the weirs or dams within the flush tank.
Another proposed solution is disclosed in U.S. Pat. No. 3,939,507 in which a cylindrical tube is placed atop the outlet to raise the minimum water level in the tank and thereby reduce the volume of water discharged during flushing. The cylindrical tube is intended to be a permanent arrangement similar to the weirs or dams previously discussed.
Also known to the applicant is the U.S. Pat. No. 1,718,744 which discloses the use of a weight to close the outlet valve upon release of the operating handle such that a minimal amount of water is discharged in the process of flushing the toilet.
Those patents known to the applicant which may be considered noteworthy as being structurally similar to the present invention are U.S. Pat. Nos. 2,731,647, 2,803,833, 3,909,856, and 4,003,097. However, in each instance, the interior structure of an existing or conventional water closet would have to be drastically altered, and, unlike with the application of the present invention, would generally require the services of a professional plumber. For example, in substantially all of the patents cited, it would be necessary to remove the preexisting outlet or spud valve in order to accommodate the structure disclosed in the patent. Furthermore, in many instances, the prior art has disclosed complex constructions which are expensive to manufacture and maintain and which are not readily applicable to existing flush tanks.